An
artist's depiction of the twin spacecraft that comprise NASA's Gravity
Recovery And Interior Laboratory (GRAIL) mission. During the GRAIL
mission's science phase, spacecraft (Ebb and Flow) transmit radio
signals precisely defining the distance between them as they orbit the
Moon in formation. Credit: NASA/JPL-Caltech/MIT

A
NASA mission to study the Moon from crust to core has completed its
prime mission earlier than expected. The team of NASA's Gravity Recovery
and Interior Laboratory (GRAIL) mission, with twin probes named Ebb and
Flow, is now preparing for extended science operations starting August
30 and continuing through December 3, 2012.

The GRAIL mission has
gathered unprecedented detail about the internal structure and
evolution of the Moon. This information will increase our knowledge of
how Earth and its rocky neighbors in the inner solar system developed
into the diverse worlds we see today.